The background of the present invention is the field of capsules which contain beverage or other comestibles ingredients. By means of an interaction of these ingredients with a liquid, a beverage such as coffee, tea or other comestibles, such as for example soup, can be produced. The interaction can be based on the principle of extraction of a beverage substance, the mixing or the dissolution, in presence of a liquid diluent such as water.
The capsule of the invention is more particularly adapted to contain ground coffee in order to produce a coffee beverage by injecting hot water under pressure into the capsule and obtaining a coffee beverage from the capsule.
Systems and methods for obtaining fluid comestibles from substances containing capsules are for example known from EP 512 470 A.
The principle of the extraction process as described in the prior art can be summarized as follows.
An initially sealed capsule is inserted in a dedicated chamber of the system in which water injection means are provided which enable water to be provided to the capsule, e.g., by injection. In the chamber, dedicated opening means are provided which generate at least one opening in a first wall of the capsule. Accordingly, water entering the capsule through the opening in a first wall is made to interact with ingredients contained in the capsule while traversing the interior of the capsule and is then made to leave the capsule through at least one opening/perforation created in a second wall of the capsule. As a result of the interaction between water and the ingredients in the capsule, a beverage or other comestible can be produced.
The capsule can be gas-tightly closed before use to ensure the freshness of the ingredients within a given shelf life. The capsule can also just form a closed but not necessarily a gas-tight enclosure and be packed in a gastight package individually or in group.
Therefore, the capsules can be closed by, at least, liquid-impermeable walls, preferably liquid- and gas-impermeable walls, at least one of which is pierced only during use, for injection of water, for example, when the capsule is introduced in the device.
In the known beverage preparation devices, the capsule is pierced by introduction of a piercing member which is foreign to the capsule, i.e. the piercing member is provided at the beverage preparation device. In general, an outer wall of the capsule is pierced by introducing the piercing member in the outer wall. Accordingly, a liquid can be injected into the capsule through the holes or apertures generated in the outer wall of the capsule.
However, the known embodiments suffer the disadvantage that certain capsules can be difficult to pierce in a repeated manner. Especially with capsules comprising plastic walls, the material can be relatively difficult to pierce and the piercing members of the device may become blunt relatively rapidly. Therefore, new capsules can no longer be pierced and the beverage preparation device has to be returned to a service or maintenance station for repairing or replacing the piercing members.
Moreover, the piercing means of the known devices only provide a single injection pattern in the capsule. It is therefore not possible to vary the manner the liquid is injected into the capsule, such as the number of holes produced in the body of the capsule, the direction of the injection, the depth of the injection, etc., unless a specific injection commuting system as described in WO 2005/020768 is provided at the device which however can be more complex to produce.
The known devices further suffer the disadvantage that when the capsules are removed from the device, the piercing members of the device disengage from the capsule at the same time. As a result, large holes in the capsule provide a potential leakage from beverage residues such as coffee solids. A known solution for this problem is the provision of filter means in the capsule which prevent the exit or draining of such residues such as proposed in EP 1 165 398. However, this solution requires the provision of an additional element in contact with the beverage ingredients within the ingredient compartment of the capsule. Therefore, the additional element must be made of a food grade and usually inert material. The filter must also be sealed on the inner surface of the capsule and therefore be compatible in sealing with the material of the body of the capsule. Accordingly, it is relatively difficult to find a corresponding material fulfilling all the required features.
Another disadvantage of the prior art opening means is that the piercing member generally comes in contact with the ingredients provided within the capsule when piercing a wall or a face of the capsule. This is particularly disadvantageous for certain ingredients such as infant formula for which it is necessary to clean or sanitize the piercing member after each cycle such as described in PCT/EP08/057,979.
WO 2006/030461 relates to a capsule which comprises a piercing element turned upwards in direction of an outer membrane. Hence, the piercing element is facing the outer membrane of the capsule from inside. Accordingly, piercing of the membrane of the capsule is obtained by fluid pressure which presses the membrane against sharp elements provided within the capsule. However, this solution has several drawbacks. In particular, the membrane may easily be ruptured by accident. Hence a user may hurt him/herself due to the sharp protruding piercing members facing the exterior of the capsule. Moreover, if the membrane is pierced before use of the capsule, this may cause a rapid degradation of the ingredients.
The present invention therefore aims at providing a solution to the above-described problems. The invention also aims at other objects and particularly at providing solutions to other problems as will appear in the rest of the present description.